By Steve Borel
Many Louisiana residents who have been outside during the day recently have probably noticed a fast-flying gnat flying around and buzzing their heads. The gnats often bite around the head and neck. People who have been bitten may have noticed a red swelling reaction.
The species are black flies (family Simuliidae) that develop in bayous and flooded areas like battures. There is one generation per year that can occur in late winter to early spring. Adult populations exist for approximately one month, and the eggs deposited by the females begin to develop for the following year. Historically, in the Mississippi River Valley, the emergence of massive swarms of Southern buffalo gnats was associated with the death of livestock. Acute toxemia and anaphylactic shock can be caused by toxins in the saliva of feeding black flies. The black fly Cnephia ornithophilia prefers birds to livestock. The turkey gnat also is a serious pest of chickens and turkeys.
What to do: This outbreak will probably last for 2-3 weeks.
For humans — hats, bandanas and other clothing can be treated with permethrin clothing repellent as an effective way to lower annoyance. Several products available can be found in sporting goods stores and online for protection. Clothing is treated and then allowed to dry for a couple of hours, and then you have effective for protection for weeks, even with multiple washing. Insect repellents containing DEET also can provide temporary relief.
In general, black flies will not enter barns and other enclosures. Protecting livestock, pets or birds during the day can be achieved by housing them in the darker recesses of enclosures. Since the black flies are diurnally active, animals can be turned out during the night.
Protecting animals with insecticides – products containing permethrin are available for most animals other than cats and are often effective depending upon application and formulation.